Fix: Cursor missing in omnibox after entering a alphabet in NTP 'Search box'

ui/views/controls/textfield/textfield.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/controls/textfield/textfield.h"
 
 #include <string>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
@@ skipping 437 matching lines @@
   GetRenderText()->set_selection_background_focused_color(
       GetSelectionBackgroundColor());
   SchedulePaint();
 }
 
 bool Textfield::GetCursorEnabled() const {
   return GetRenderText()->cursor_enabled();
 }
 
 void Textfield::SetCursorEnabled(bool enabled) {
+  if (GetRenderText()->cursor_enabled() == enabled)
+    return;
+
   GetRenderText()->SetCursorEnabled(enabled);
+  UpdateCursorViewPosition();
+  UpdateCursorVisibility();
 }
 
 const gfx::FontList& Textfield::GetFontList() const {
   return GetRenderText()->font_list();
 }
 
 void Textfield::SetFontList(const gfx::FontList& font_list) {
   GetRenderText()->SetFontList(font_list);
   OnCaretBoundsChanged();
   PreferredSizeChanged();
@@ skipping 506 matching lines @@
 
 void Textfield::OnPaint(gfx::Canvas* canvas) {
   OnPaintBackground(canvas);
   PaintTextAndCursor(canvas);
   OnPaintBorder(canvas);
 }
 
 void Textfield::OnFocus() {
   GetRenderText()->set_focused(true);
   if (ShouldShowCursor()) {
-    UpdateCursorView();
+    UpdateCursorViewPosition();
     cursor_view_.SetVisible(true);

[msw, 2017/03/10 21:04:30]

optional nit: should this pass ShouldShowCursor(), or just call
UpdateCursorVisibility() and remove the blinking check below, instead of passing
|true|? Feel free to pursue that in a separate CL if you're hesitant to change
that here.

[yiyix, 2017/03/13 04:02:16]

Since it is a fix of dev block bug, I hesitate to make any functionality
changed. I will include it in a separate CL. Thank you so much for point out.

   }
   if (GetInputMethod())
     GetInputMethod()->SetFocusedTextInputClient(this);
   OnCaretBoundsChanged();
   if (ShouldBlinkCursor())
     StartBlinkingCursor();
   if (use_focus_ring_) {
     FocusRing::Install(this, invalid_
                                  ? ui::NativeTheme::kColorId_AlertSeverityHigh
                                  : ui::NativeTheme::kColorId_NumColors);
@@ skipping 906 matching lines @@
   View::SetBorder(std::move(border));
 }
 
 void Textfield::UpdateAfterChange(bool text_changed, bool cursor_changed) {
   if (text_changed) {
     if (controller_)
       controller_->ContentsChanged(this, text());
     NotifyAccessibilityEvent(ui::AX_EVENT_TEXT_CHANGED, true);
   }
   if (cursor_changed) {
-    UpdateCursorView();
-    cursor_view_.SetVisible(ShouldShowCursor());
-    if (ShouldBlinkCursor())
-      StartBlinkingCursor();
-    else
-      StopBlinkingCursor();
+    UpdateCursorViewPosition();
+    UpdateCursorVisibility();
     NotifyAccessibilityEvent(ui::AX_EVENT_TEXT_SELECTION_CHANGED, true);
   }
   if (text_changed || cursor_changed) {
     OnCaretBoundsChanged();
     SchedulePaint();
   }
 }
 
-void Textfield::UpdateCursorView() {
+void Textfield::UpdateCursorVisibility() {
+  cursor_view_.SetVisible(ShouldShowCursor());
+  if (ShouldBlinkCursor())
+    StartBlinkingCursor();
+  else
+    StopBlinkingCursor();
+}
+
+void Textfield::UpdateCursorViewPosition() {
   gfx::Rect location(GetRenderText()->GetUpdatedCursorBounds());
   location.set_x(GetMirroredXForRect(location));
   cursor_view_.SetBoundsRect(location);
 }
 
 void Textfield::PaintTextAndCursor(gfx::Canvas* canvas) {
   TRACE_EVENT0("views", "Textfield::PaintTextAndCursor");
   canvas->Save();
 
   // Draw placeholder text if needed.
@@ skipping 144 matching lines @@
                             this, &Textfield::OnCursorBlinkTimerFired);
 }
 
 void Textfield::StopBlinkingCursor() {
   cursor_blink_timer_.Stop();
 }
 
 void Textfield::OnCursorBlinkTimerFired() {
   DCHECK(ShouldBlinkCursor());
   cursor_view_.SetVisible(!cursor_view_.visible());
-  UpdateCursorView();
+  UpdateCursorViewPosition();
 }
 
 }  // namespace views